Test Code LAB877, LAB7000, LAB7001 Mycobacteriology (AFB) Culture
Methodology
Testing Algorithm:
- Positive acid-fast stain on a respiratory related specimen (i.e., bronchial alveolar lavage, bronchial washing, induced sputum, sputum, tracheal aspirate or pleural fluid) – PCR for Mycobacterium tuberculosis complex (MTBC) will be performed.
- PCR for Mycobacterium tuberculosis complex (MTBC) will be performed on respiratory related specimens (i.e. bronchial alveolar lavage, bronchial washing, induced sputum, sputum, tracheal aspirate, or pleural fluid) when ordered. Refer to Mycobacterium tuberculosis PCR (LAB7356).
Notes:
- Acid-fast stain is not routinely performed on cerebrospinal fluid (CSF). Call Microbiology Laboratory at 314-362-3898 if stain is medically indicated.
- For AFB culture without acid-fast stain, order LAB877.
- For AFB culture with acid-fast stain, order LAB7000. If specimen type is lung/respiratory related, then acid-fact stain will be performed.
- For AFB culture with acid-fast stain on respiratory specimen from Cystic Fibrosis (CF) patient, order LAB7001.
- For specific specimen requirements for blood specimens, see Mycobacteria (AFB) Blood Culture (LAB246).
Performing Laboratory
Barnes-Jewish Hospital Laboratory
Specimen Requirements
Acceptable Specimens:
Abscess, aspirate, or wound: ≥1 mL in a leakproof screw-capped, sterile container or, if unable to obtain fluid, 1 ESwab per test request in sterile collection tube.
Biopsy or tissue: ≥1 g in a leakproof screw-capped, sterile container.
Bronchial or tracheal: ≥5 mL in a leakproof screw-capped, sterile container.
Eye: conjunctiva and cornea - 1 ESwab Minitip Collection Kit; ocular fluid (anterior chamber, aqueous humor, vitreous) - ≥0.5 mL in a leakproof screw-capped, sterile container.
Sterile Fluids (pericardial, pleural, synovial, etc.): ≥1 mL in a leakproof screw-capped, sterile container. Note: Pleural fluid: as much as possible.
CSF: >10 mL in a leakproof screw-capped, sterile container.
Gastric aspirate: ≥5 mL in a leakproof screw-capped, sterile container.
Sputum: ≥5 mL in a leakproof screw-capped, sterile container.
Urine: ≥40 mL in a leakproof screw-capped, sterile container.
Unacceptable Specimens:
Stool
Specimen collected with ESwab Collection Kit is unacceptable if received without fluid or swab in the transport tube.
Collection Procedure:
Note: Specimen source is required.
Abscess, Aspirate, or Wound
1. Disinfect surface of abscess or wound.
2. Aseptically collect purulent material by aspiration (≥1 mL) or by using an ESwab. Frequently, viable organisms are only associated with abscess wall, so adequately sample this area. If material is aspirated, aseptically inject specimen into a leakproof screw-capped, sterile container or a plain, red-top tube.
3. If ESwab is used, return ESwab into transport tube following instructions on kit.
4. Maintain sterility and tranport promptly to laboratory.
5. If transport is delayed, keep specimen at room temperature.
Biopsy or Tissue
1. Aseptically collect ≥1 g of tissue from border of lesion. Because there may be only a few viable organisms in a lesion, the specimen must be large enough to permit their recovery.
2. Place specimen in a leakproof screw-capped, sterile container.
3. Maintain sterility and transport promptly to laboratory.
4. If transport is delayed, keep specimen at room temperature.
Bronchial or Tracheal
1. Aseptically collect ≥5 mL of fluid.
2. Place specimen in a leakproof screw-capped, sterile container.
3. Maintain sterility and transport promptly to laboratory.
4. If transport is delayed, refrigerate specimen.
CSF
1. Aseptically collect >10mL of fluid.
2. Place specimen in a leakproof screw-capped, sterile container.
3. Maintain sterility and transport promptly to laboratory.
4. If transport is delayed, keep specimen at room temperature.
Eye
1. Conjunctiva or cornea-Call Barnes-Jewish Hospital Laboratory Customer Service at 314-362-1470 to obtain ESwab Minitip Collection Kit.
A. Collect specimen before application of topical anesthetics because topical anesthetics possess antimicrobial activity.
B. Cleanse skin around eye with mild antiseptic.
C. Gently remove makeup and ointment with sterile cotton and saline.
D. Collect specimen by passing ESwab 2 times over lower conjunctiva or over cornea. Avoid eyelid border and lashes (culture these separately in a similar fashion, if indicated).
E. Place ESwab in transport tube following instructions on kit.
F. Maintain sterility and transport promptly to laboratory.
G. If transport is delayed, keep specimen at room temperature.
2. Ocular fluid (anterior chamber, aqueous humor, vitreous)
A. Aseptically collect ≥0.5 mL of fluid.
B. Place specimen in a leakproof screw-capped, sterile container.
C. Maintain sterility and forward promptly.
D. If transport is delayed, keep specimen at room temperature.
Sterile Fluid (Pericardial, Pleural, Synovial, etc.)
1. Aseptically collect ≥1 mL of fluid.
2. Place specimen in a leakproof screw-capped, sterile container.
3. Maintain sterility and transport promptly to laboratory.
4. If transport is delayed, keep specimen at room temperature.
Gastric Aspirate
1. Aseptically collect ≥5 mL of an early-morning specimen in a leakproof screw-capped, sterile container. Specimen received in the laboratory >4 hours between specimen collection and the time the specimen is processed in the laboratory will be canceled. Specimen received after 9:00 AM will be canceled. It is optimal to collect a specimen each day for 3 consecutive days.
2. Maintain sterility and transport promptly to laboratory.
Sputum
1. Aseptically collect early-morning specimen in a leakproof screw-capped, sterile container. It is optimal to collect a specimen each day for 3 consecutive days. (Saliva is not acceptable.)
2. Instruct patient to brush his/her teeth and rinse mouth well with water.
3. Have patient remove dentures.
4. Instruct patient to take a deep breath, hold it momentarily, and then cough deeply and vigorously into container. Collect ≥5 mL of discharged material.
5. Maintain sterility and transport promptly to laboratory.
6. If transport is delayed, refrigerate specimen.
Urine
1. Aseptically collect ≥40 mL of a first-morning urine specimen.
2. Place specimen in a leakproof screw-capped, sterile container. (24-hour specimen is not acceptable.)
3. Send specimen refrigerated. Maintain sterility and transport promptly to laboratory.
Specimen Transport Temperature
Ambient/Refrigerate OK
Reference Values
No growth of acid-fast bacilli after 8 weeks.
Literature Reference:
Della-Latta P. Mycobacteriology and antimycobacterial susceptibility testing. In: Leber, Amy, ed. Clinical microbiology procedures handbook. 4th ed. Washington DC: American Society for Microbiology; 2016;7.1-7.6.
Day(s) Test Set Up
Monday through Sunday
Cut-off time: 0900
Turnaround Time:
STAT: not available
Routine: final negative report after 8 weeks of incubation
Test Classification and CPT Coding
87116 - Culture, Mycobacterium
87206 - Smear fluorescent, acid-fast (if appropriate)
Additional Information
For BJH Laboratory Use Only
Minimum Volume:
Abscess or wound: 0.5 mL in a leakproof screw-capped, sterile container or, if unable to obtain fluid, 1 ESwab per test request in sterile collection tube
Aspirate: 0.5 mL in a leakproof screw-capped, sterile container
Biopsy or tissue: any amount in a leakproof screw-capped, sterile container
CSF: 10mL
Eye: conjunctiva or cornea - 1 ESwab Minitip Collection Kit; ocular fluid (anterior chamber, aqueous humor, vitreous) - 0.5 mL in a leakproof screw-capped, sterile container
Sterile Fluids (pericardial, pleural, synovial, etc.): 0.5 mL (Pleural fluid: as much as possible) in a leakproof screw-capped, sterile container
Gastric Aspirate: 0.5 mL in a leakproof screw-capped, sterile container
Respiratory: 0.5 mL in a leakproof screw-capped, sterile container
Urine: 10 mL in a leakproof screw-capped, sterile container
Laboratory Processing Instructions:
Test performed in BJH Microbiology.